The electronic conductivity of organic materials lies between that of metals and insulators, spanning a broad range of 10−9 to 103/Ω-cm. The interest in this field can be traced back to early 1900s when the photoconduction of solid anthracene was discovered. A considerable amount of research was devoted to understand the charge transport properties of organic semiconductors starting 1950s and to potential use of organic semiconductors in electronic devices began in late 1980s.
The interest in the study of organic semiconductors in particular sparks from the fact that these organic electronic devices are easier to fabricate than traditional silicon based semiconductors that require rigorous processing techniques and high temperatures. Also organic semiconductors can be designed by computer assist modeling to improve their charge transport properties in electronic field to fit a variety of application requirements or by incorporation of functional groups in the molecules and improving their physical properties to make low temperature vapor deposition process possible, or by improving solubility in solvents that led to form semiconductor thin film by cost-effective solution deposition process.
Many organic materials have been studied as organic semiconductors. Among them arylamines were widely studied as organic photoconductors (OP) in early 1970s and later as an efficient hole transport materials for OLED devices. Fused aryl hydrocarbon molecule, more typically pentancene and its derivatives have shown the high charge mobility both processed by vapor deposition and solution coating deposition process.
The most known regular poly(3-hexylthiophene) has been studied and reported with low charge mobility and low current on/off ratio. Most recently polythionphene were studied as organic thin film transistors (OTFT) with a research focus on improving the charge mobility, easy to synthesize, good processibility and oxidative stability. These improvements can be achieved by designing the new monomers, oligomers, and polythiophene molecules with good planarity and conjugation [Applied Physics Letter, 90, 012112, 2007 and references therein]. A few of thiophene containing examples have been disclosed in U.S. Pat. Nos. 6,695,978; 6,645,401; 6,806,374; 6,841,677; 6,913,710 and were shown as follows:

3,4:3′,4′-bibenzo[b]thiophene (BBT) which has an isoelectronic structure with perylene which has been known as one of most stable organic materials. BBT has been reported and its iodine complex with very similar properties to the perylene-iodine solids, including its electrical conductivity [J. Org. Chem. Vol. 44, page 2491-2493, (1979)].

The bibenzochalcogenophenes containing S, bibenzothiophene, Se, bibenzoselenophene or Te bibenzotellurophene and its selenium analogs have a great planarity and rigid conjugation ring system. These structure features are important in improving charge mobility and stability toward environmental oxygen exposure.
Thus, there exists a need for new compounds containing a bibenzothiophene structure that provides the planarity, rigid conjugation system and charge mobility of this structure. There exists a further need for new compounds containing bibenzothiophene structures that are easily synthesized, and are readily processed either by vapor deposition to from uniform thin film or by cost-effective solution coating deposition process with good environmental oxygen exposure stability.